Molecular genetics and biology of dementia

Considerable progress has been made in our understanding of the genetics and molecular biology of dementia. In this chapter we focus predominantly on the most common form of dementia, Alzheimer’s disease (AD), but also discuss vascular dementia and frontotemporal dementia. Genetic mutations have been identified that cause Mendelian subtypes of each disorder, and in recent years genome-wide association studies have greatly aided the identification of risk genes for more common forms of disease. For example, 9 susceptibility genes have been identified in AD in the past 3 years as a result of genome-wide association studies, the first robust risk loci to be identified since APOE in 1993. This progress in genetic research is having a dramatic effect on our understanding of disease pathogenesis, by refining previous ideas and defining new primary disease mechanisms.